Disclosed herein is an aqueous ink composition comprising water; an optional co-solvent; an optional colorant; and a composite comprising a sulfonated polyester matrix having a plurality of silver nanoparticles dispersed within the matrix.
There is a growing problem related to bacterial and fungal contamination through contact with surfaces and objects especially within hospitals, medical clinics, airplanes, and cruise ships, to mention a few. Individuals suffering from gastroenteritis, for example, can easily spread the illness by touching handrails, shared utensils, elevator buttons, etc. In some cases, contamination can be deadly especially in the cases of outbreaks of gastroenteritis acquired on cruise ships caused by Noroviruses or food poisoning due to particular strains of Escherichia coli and Salmonella. Another bacterium, Staphylococcus aureus, is a major culprit for many illnesses and skin irritations. There is a type of Staphylococcus aureus that is Methicillin-resistant (known as MRSA) which is resistant to the antibiotic methicillin and other drugs in this class.
The use of an organic biocide in materials such as polymers, inks toners, etc., for preventing microbial growth, is described, for example, in U.S. Pat. No. 6,210,474, which is hereby incorporated by reference herein in its entirety. However, anti-microbial effectiveness within a printed or coated state of a printed ink or toner has not been described or demonstrated. As well, many anti-microbially active compounds are not compatible with aqueous ink jet ink formulations or include using solvents such as dimethylsulfoxide. Also, some ink jet ink compositions contain silver or even gold particles to produce metallic glossy prints, but have not been described or demonstrated to possess anti-microbial effectiveness. See, for example, U.S. Pat. No. 8,616,694, which is hereby incorporated by reference herein in its entirety, which describes an ink jet recording method including an ink composition containing a glitter pigment.
U.S. Patent Application 20130189499, which is hereby incorporated by reference herein in its entirety, describes inks which include a mixture of solvent and a silver salt biocide including a silver sulfate biocide. Here, the clear or colored ink is applied in an imagewise fashion to a substrate, with fixing the clear or colored ink to the substrate whereby an effective coating or image article is formed that provides anti-bacterial and antifungal protection.
A need remains for aqueous anti-bacterial ink compositions. Further, a need remains for aqueous anti-bacterial ink compositions having anti-microbial effectiveness within a printed or coated state of the printed ink. Further, a need remains for aqueous anti-bacterial ink compositions having anti-microbial effectiveness within a printed or coated state of the printed ink, that are environmentally friendly, and that do not require organic solvents.
The appropriate components and process aspects of the each of the foregoing U.S. Patents and Patent Publications may be selected for the present disclosure in embodiments thereof. Further, throughout this application, various publications, patents, and published patent applications are referred to by an identifying citation. The disclosures of the publications, patents, and published patent applications referenced in this application are hereby incorporated by reference into the present disclosure to more fully describe the state of the art to which this invention pertains.